Blow molded bottle with unframed flex panels

ABSTRACT

A hot-fillable, slender, blow-molded plastic bottle for use in containing hot-filled beverages. The bottle has a sidewall with various interactive zones of function. For example, some of the zones are primarily responsible for accommodating vacuum absorption, while other zones are primarily intended to rigidify the container such as by providing post strength to improve container top loading capability. Although each zone may have a primary function, each zone also aids adjacent zones in providing their functions. Thus, the entire sidewall, and not merely selected locations, reacts to the forces generated by the hot-fill process on the container.

This application claims the benefit of provisional application60/133,618 filed May 11, 1999.

FIELD OF THE INVENTION

The present invention relates to a slender bottle which integratesaesthetic and functional features without clearly segregating suchfeatures from one another. More particularly, the present inventionrelates to a slender blow-molded plastic bottle which is useful inpackaging a hot-filled beverage.

BACKGROUND OF THE INVENTION

In the packaging of beverages, especially juice, blow-molded plasticcontainers made from, for instance, PET, are used in the so-called“hot-fill” process in which containers are filled with a beverage at anelevated temperature. The hot-filled containers are promptly sealed andare permitted to cool resulting in internal pressure and temperaturechanges that reduce the volume of the sealed container.

It is known to provide hot-fillable containers with a series ofwell-defined, spaced-apart vacuum flex panels to compensate for theinternal volume reduction. The vacuum flex panels provide a sufficientamount of flexure without adversely affecting the structural integrityand aesthetic appearance of the hot-filled container. The adjacentportions of the container, such as the so-called lands, or columns,which are located between, above, and below the flex panels, areintended to resist any deformations which would otherwise be caused byhot-fill processing. Wall thickness variations, or geometric structures,such as ribs, projections and the like, can be utilized to preventunwanted distortion. Generally, the typical hot-fillable containerstructure is provided with certain pre-defined areas which flex toaccommodate volumetric changes and certain other pre-defined areas whichremain unchanged.

An example of a hot-fillable container having a plurality of flex-panelsis illustrated in U.S. Design Pat. No. D.366,416 which is owned by theassignee of the present application. The hot-fill bottle haswell-defined flex panels which are distinctly visually apparent prior tofilling and which accommodate vacuum induced distortions after filling,capping and cooling. The container also has other geometric structureswhich are completely segregated from the flex panels, which aredistinctly visually apparent prior to filling, and which resiststructural change caused by volume reduction. Typically, all of thesestructures are framed about their entire peripheries and are completelyseparated from the bottle's aesthetic features which are usually limitedto the dome of the container. For example, flex panels are oftenindented from adjacent vertically disposed lands and fromcircumferential upper and lower label mount regions. Conventionally, theindented panels merge into the adjacent lands via various stepped-shapedwalls, grooves, projections or like structures.

Other examples of container sidewalls having flexible panels aredisclosed in U.S. Pat. No. 4,749,092 issued to Sugiura et al.; U.S. Pat.No. 3,923,178 issued to Welker III; U.S. Pat. No. 4,497,855 issued toAgrawal et al.; U.S. Pat. No. 5,740,934 issued to Brady; and U.S. Pat.No. 5,704,504 issued to Bueno. The Sugiura, Welker and Agrawal patentsdisclose inwardly deflecting vacuum flex panels which are locatedbetween substantially planar lands; the Bueno patent discloses inwardlydeflecting panels which are located between spiral-shaped grooves; andthe Brady patent discloses outwardly deflecting panels which intersectat vertically disposed corners.

Although various ones of the above referenced containers may functionsatisfactorily for their intended purposes, there is a need for ahot-fillable blow molded bottle which integrates functional andaesthetic components in such a manner as to provide a package havingenhanced visual interest. Such a package is particularly desirable insingle-serve sizes wherein slenderness and single-handed gripability aredesirable features.

OBJECTS OF THE INVENTION

With the foregoing in mind, a primary object of the present invention isto provide a hot-fillable bottle which integrates vacuum absorption,structural reinforcement, and other functional features with aestheticand ergonomic properties by providing various interactive functionalzones in the container structure.

Another object of the present invention is to provide a bottle having aplurality of alternating non-framed flex panels and non-framed lands, orcolumns, which laterally merge together directly and which are jointlyreactive to hot-fill process forces acting thereon.

A further object is to provide a blow-molded, plastic, slender bottlehaving a grip structure which both enhances the structural integrity ofthe container and the visual appearance of the container.

SUMMARY OF THE INVENTION

More specifically, the present invention provides a blow-molded plasticcontainer having a neck with an upstanding threaded finish, aclose-ended base, and a tubular sidewall located between the base andthe neck. The sidewall includes, in an alternating pattern, a pluralityof circumferentially-spaced, vertically-elongate columns and a pluralityof circumferentially-spaced substantially smooth-surfaced panels. Eachof the columns, as formed, is outwardly convex in horizontal crosssection, and each of the panels, as formed, is inwardly concave inhorizontal cross section such that each of the panels extends laterallybetween and directly connects to an adjacent pair of the columns. Inaddition, each of the columns, as formed, is outwardly convex invertical cross-section, and each of the panels, as formed, is inwardlyconcave in vertical cross section such that each of the columns andpanels have opposite ends which merge directly into adjacent portions ofthe container.

Functionally, each of the panels flexes outwardly to expand the volumeof the container during hot-filling, and each of the panels flexesinwardly in response to a reduction in internal volume when thecontainer is capped and permitted to cool. The inward deflection of thepanels interactively increases the horizontal cross-sectional convexityof each column and decreases the vertical cross-sectional convexity ofeach column. The vertical straightening of each column and the lateralpinching of each column combine to structurally strengthen thecontainer.

The aforedescribed structure is particularly suited for slender,single-serve size bottles.

In a preferred embodiment, a plurality of vertically-aligned fingeralignment projections are formed integrally on each of the columns todefine finger grip locations, to structurally reinforce the columns, andto provide points of visual interest.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of the presentinvention should become apparent from the following description whentaken in conjunction with the accompanying drawings, in which:

FIG. 1 is an elevational view of a container embodying the presentinvention;

FIG. 2 is a vertical cross-sectional view taken along line 2—2 of thecontainer illustrated in FIG. 1;

FIG. 3 is a horizontal cross-sectional view taken along line 3—3 of thecontainer illustrated in FIG. 1;

FIG. 4 is a horizontal cross-sectional view taken along line 4—4 of thecontainer illustrated in FIG. 1,

FIG. 5 is an elevational view of a second embodiment of a containeraccording to the present invention;

FIG. 6 is a vertical cross-sectional view taken along line 6—6 of thecontainer illustrated in FIG. 5;

FIG. 7 is a horizontal cross-sectional view taken along line 7—7 of thecontainer illustrated in FIG. 5;

FIG. 8 is a horizontal cross-sectional view taken along line 8—8 of thecontainer illustrated in FIG. 5;

FIG. 9 is a horizontal cross-sectional view taken along line 9—9 of thecontainer illustrated in FIG. 5;

FIG. 10 is an elevational view of a third embodiment of a containeraccording to the present invention; and

FIG. 11 is an elevational view of the container illustrated in FIG. 10rotated 30° about a vertical axis extending centrally through thecontainer.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

One embodiment of a slender bottle, or container, 10 according to thepresent invention is illustrated in FIG. 1. The container 10 has a dome12, a close ended base 14 and a sidewall 16 located between the dome andbase. An upper portion of the dome 12 includes an upstanding threadedfinish 18 to which a closure, such as a cap, (not shown) can beattached. A lower portion of the dome 12 includes a circumferentialgroove, or waist, 20 which provides hoop strength to the bottle toresist ovalization distortion which may otherwise result due tohot-filling and to stiffen the transition between the lower portion ofthe dome and the sidewall. Optionally, a label can be mounted on thedome 12 between the finish 18 and the groove 20.

Certain novel aspects of the illustrated preferred embodiment arelocated in the sidewall 16 which is inset between an upper bumper 16 aand a lower bumper 16 b and lies entirely within an imaginarycylindrical plane “P” tangent to the outer surface of both.Functionally, the sidewall 16 is capable of expanding when the bottle isfilled and is capable of accommodating vacuum absorption when thehot-filled bottle is capped and permitted to cool. In addition, thesidewall 16 is provided with structure which enhances grip-ability ofthe container 10 and the aesthetic visual appearance of the container10.

The sidewall 16 is provided with various interactive zones of function.For example, some of the zones are primarily responsible foraccommodating vacuum absorption, while other zones are primarilyintended to rigidify the container such as by providing post strength toimprove container top loading capability. Although each zone may have aprimary function, each zone also aids adjacent zones in providing theirfunctions. Thus, the entire sidewall 16, and not merely selectedlocations, reacts to the forces generated by the hot-fill process on thecontainer 10.

To this end, a plurality of unframed and substantially smooth-surfacedflex panels 22 are provided on the sidewall 16 in an alternating patternwith a plurality of vertically elongate columns 24. The panels 22provide zones of expansion and vacuum absorption, and the columns 24provide structural reinforcement zones. Both the panels 22 and thecolumns 24 react to the forces created by hot-fill processing.

In the “as-formed” condition, ie. after blow-molding but beforehot-filling, and in the absence of any internal or external appliedforces, the panels 22 are slightly inwardly concave. This is bestillustrated in the vertical cross-section of the right hand side of FIG.2, and in the horizontal cross sections illustrated in FIGS. 3 and 4.The deepest inset portion 26 of each panel 22 is located at theintersection of its vertical centerline 28 and its horizontal centerline30. In the embodiment illustrated in FIGS. 1-4, each panel 22 issubstantially rectangular and is not surrounded by any framing structuresuch as a stepped wall portion. Rather, all the peripheral edges of eachpanel 22 merge directly into the adjacent portions of the container aswill be discussed.

In the as-formed condition, the columns 24 are slightly outwardlyconvex. This is best illustrated in the vertical cross-section of theleft hand side of FIG. 2, and in the horizontal cross sectionsillustrated in FIGS. 3 and 4. Each column 24 is substantiallyrectangular and is not surrounded by any distinct framing structure,such as a stepped wall. Rather, each column 24 merges smoothly anddirectly into the adjacent portions of the container. For example, thelateral edges of each panel 22 merge directly into the side edges of anadjacent pair of columns 24. The juncture of the panels 22 and columns24 are not delineated by other structure; rather, they smoothlytransition directly into one another. As best illustrated in FIGS. 1 and2, the upper and lower edges of the panels 22 and the columns 24 alsomerge directly into the upper and lower bumpers 16 a and 16 b,respectively.

Preferably, the deepest inset portion 26 of each panel 22 is inset intothe container 10 an equal pre-determined distance to the most outwardlyprojecting portion of each column. For example, if each panel 22 isinset approximately 2 mm from an imaginary container datum plane “D”as-formed, then each column projects 2 mm from the container datum plane“D” as-formed. The “container datum plane ‘D’” is defined as animaginary cylindrical plane about which the panels bow inwardly andabout which the columns bow outwardly. See the dashed line “D” in FIG.4.

In another embodiment, which provides certain additional structural andfunctional advantages over the first-described embodiment, isillustrated in FIGS. 5-9. The container 110 includes a base 114, asidewall 116 and a dome 112 having a finish 118. In this embodiment,each column, such as the column 124, has an hourglass-shape in verticalelevation, with its narrowest region located at the vertical median ofthe sidewall 116 as determined by section line 7—7. From there, thecolumn flares outwardly in both upward and downward directions. Eachpanel 122 between adjacent columns 124 is complementary and has itswidest portion at the sidewall median and narrows therefrom in bothupward and downward directions. Both the columns and the panels mergesmoothly outwardly with the upper and lower bumpers 116 a and 116 b,respectively.

In this embodiment, each of the finger grip protrusions 132, asdiscussed below, is of equal size, shape and radial extent providingbetter grip-ability without sacrificing flexural performance.

When the containers 10, 110 are hot-filled with a beverage, each panel22, 122 initially deflects outwardly slightly, as best shown forcontainer 110 exaggerated in dot-dash line in FIG. 6, to increase thevolume of the containers 10, 110. After the containers 10 and 110 arehot-filled, capped and permitted to cool, each panel 22, 122 deflectsinwardly to effectively reduce the volume of each container 10 and 110,as best illustrated greatly exaggerated for container 110 by the dashedlines in FIGS. 6 and 7-9.

Each of the columns 24, 124 also reacts to the forces created in thehot-filled, capped and cooled containers 10 and 110. In horizontalcross-section, the convexity of each column 24, 124 increases due to thelateral pinching of the inwardly deflecting adjacent panels 22, 122. Invertical cross-section, each column 24, 124 straightens. The combinationof the lateral pinching and the vertical straightening creates morecolumn structure as more vacuum develops in the container. The increasein column structure increases the post strength provided by the columns24, 124 and provides the filled and capped containers 10 and 110 withincreased top loading capability. The intended altered shape of thecolumns 24, 124 also aids in resisting unwanted container distortion andprovides enhanced visual aesthetic interest in the container. Note thedeflection relative to the container datum plane “D” in FIG. 7.

Preferably, each column 24, 124 is provided with a plurality ofvertically aligned protrusions 32, 132 on about one inch centers. Invertical elevation, the protrusions are defined by laterally undulatinglines of inflection 34, 134 and radially undulating surfaces 36, 136.The outward extent of the radially-undulating surfaces 36 may vary inradial extent, from maximum at the top to minimum at the bottom, such asillustrated in FIG. 1, or may be of equal extent such as illustrated inthe embodiment of FIG. 5. The outward protrusions 32, 132 definetherebetween valleys 38, 138 affording finger placement locations toimprove gripability of the container. The pattern of protrusions 32, 132also provides visual interest and structurally reinforces the columns24, 124 at certain desired locations while affording the desired flexureat certain other desired locations.

The present invention is particularly suited for use in slender bottles,ie. bottles having a predetermined slenderness ratio. Slenderness ratioas used herein is the length of the bottle 10, of FIG. 1, measuredaxially from the upper edge 18 a of the finish 18 to the bottom of thestanding ring 14 a of the base 14 divided by the mean diameter of thesidewall 16, or body portion, located between the bottom of the dome 12and the base 14. In the illustrated bottle 10, the slenderness ratio is3.3:1. The bottle 10 is drawn to full scale. In has an overall length ofabout 22.9 cm (9 inches) and a 0.7 liter (24 ounce) filled capacity.

By way of example, and not by way of limitation, each bottle, such asthe bottle 10, may be designed to contain between about a 0.2 liters(about 8 ounces) to about 1.9 liters (about 64 ounces) of a beverage.The sidewall 16 may include any number of panels 22, 122 and columns 24,124, such as in a range of two through ten. The deepest inset portion 26of each panel in the as-formed condition of the container relative tothe container datum plane “D” is about 1 to about 4 mm. Thecircumferential groove 20 in the dome 12 is approximately 6 to 7 mm indepth and approximately 4 to 5 mm in height. The filled and cappedcontainers 10 are capable of being packed and shipped in an efficientamount of space because the panels 22 of one container's sidewallinterdigitate with the columns 24 of the adjacent containers to minimizepacking volume.

A third embodiment of the present invention is provided by container 210as illustrated in FIGS. 10 and 11. The hot-fillable plastic container210 has a dome 212 with a finish 218, a lower sidewall 216 adjacent abase 214, and a substantially cylindrical intermediate sidewall 234 towhich a label (not shown) can be secured. The lower sidewall 216includes six vertically-elongate unframed flex panels 222 in analternating array with six vertically-elongate columns 224 which, whenhot-filled, function similar to the unframed flex panels and columns asdisclosed above for containers 10 and 110.

Thus, the present invention provides a hot-fillable container whichintegrates various functional and aesthetic features without clearlysegregating the features. Unframed panels and columns interact toprovide vacuum absorption functions and structural reinforcementfunctions. As more vacuum develops in the container, greater structuralfunctions develop in the container sidewall to provide a container whichis functional, structurally strong and visually aesthetic.

Various modifications to the container are contemplated. For instance,such modifications may include the use of an odd or an even number ofpanels, vacuum absorption and structural zones located in the dome ofthe container, and finger grips provided by indentations instead ofprotrusions.

While preferred embodiments of containers having a sidewall withunframed flex panels have been described, various modifications,alterations, and changes may be made without departing from the spiritand scope of the present invention as defined in the appended claims.

What is claimed is:
 1. A blow-molded plastic bottle (10, 110, 210)having a dome (12, 112, 212) with an upstanding finish (18, 118, 218), abase (14, 114, 214), and a substantially tubular sidewall (16, 116, 216)between the base (14, 114, 214) and the dome (12,112, 212), saidsidewall (16, 116, 216) comprising: an alternating pattern of aplurality of circumferentially-spaced vertically-elongate columns (24,124, 224) and a plurality of circumferentially-spaced substantiallysmooth-surfaced panels (22, 122, 222); each of said columns (24, 124,224), as formed, being outwardly convex in horizontal cross section andeach of said panels (22, 122, 222), as formed, being inwardly concave inhorizontal cross section with each of said panels (22, 122, 222)extending laterally between and connecting directly to an adjacent pairof said columns (24, 124, 224); and each of said columns (24, 124, 224),as formed, being outwardly convex in vertical cross section and each ofsaid panels (22, 122, 222), as formed, being inwardly concave invertical cross section with each of said columns (24, 124, 224) andpanels (22, 122, 222) having opposite ends merging directly intoadjacent portions of the bottle (10, 110, 210).
 2. A blow-molded plasticbottle (10, 110, 210) according to claim 1, wherein each of said panels(22, 122, 222) flexes outwardly during hot-filling and inwardly inresponse to a reduction in internal volume when the bottle (10, 110,210) is capped and permitted to cool; and wherein said inward deflectionof said panels (22, 122, 222) increases the horizontal cross-sectionalconvexity of each of said columns (24, 124, 224), whereby said increasedhorizontal cross-sectional convexity structurally enhances bottlestrength.
 3. A blow-molded plastic bottle (10, 110, 210) according toclaim 2, wherein each of said as-formed outwardly convex verticalcross-sections of each column (24, 124, 224) straightens in response tothe reduction in internal volume when the bottle (10, 110, 210) ishot-filled, capped and permitted to cool; and wherein said verticalstraightening structurally enhances the strength of the bottle (10, 110,210).
 4. A blow-molded plastic bottle (10, 110) according to claim 3,further comprising a plurality of vertically-aligned finger alignmentprotrusions (32,132) formed integrally on each of said columns (24,124).
 5. A blow-molded plastic bottle (10, 110) according to claim 4,wherein said sidewall (16, 116) has a number of said panels (22, 122) ina range of two through ten and an equal number of said columns (24,124).
 6. A blow-molded plastic bottle (10, 110) according to claim 5,wherein said sidewall (16, 116) has five of said panels (22, 122) andfive of said columns (24, 124) affording side-by-side packing with likebottles (10, 110) in a minimum of space with said columns (24, 124) ofone bottle (10, 110) interdigitating with said panels (22, 122) ofadjacent bottles (10, 110).
 7. A slender blow-molded plastic bottle (10,110, 210) comprising: an upper portion with a dome (12, 112, 212) havingan upstanding finish (18, 118, 218) capable of being sealed with aclosure; a lower portion having a base (14, 114, 214); and a generallytubular intermediate sidewall portion (16, 116, 216) between said upperand lower portions, said sidewall portion (16, 116, 216) being formedwith a plurality of circumferentially-spaced vertically-elongate columns(24, 124, 224) in an alternating pattern with a plurality ofcircumferentially-spaced substantially smooth-surfaced panels (22, 122,222); each of said columns (24, 124, 224), as formed, being outwardlyconvex in horizontal cross section and each of said panels (22, 122,222), as formed, being inwardly concave in horizontal cross section suchthat each of said panels (22, 122, 222) extends laterally between andconnects directly to an adjacent pair of said columns (24, 124, 224);each of said columns (24, 124, 224), as formed, being outwardly convexin vertical cross section and each of said panels (22, 122, 222), asformed, being inwardly concave in vertical cross section such that eachof said columns (24, 124, 224) and panels (22, 122, 222) has oppositeends which merge directly into adjacent portions of the bottle (10, 110,210); each of said panels (22, 122, 222) flexing outwardly to expand thevolume of the bottle (10, 110, 210) during hot-filling and each of saidpanels (22, 122, 222) flexing inwardly in response to a reduction ininternal volume after the bottle (10, 110, 210) is capped and permittedto cool; and said inward deflection of said panels (22, 122, 222)functioning to increase the horizontal cross-sectional convexity of eachof said columns (24, 124, 224) and of decreasing the verticalcross-section convexity of each of said columns (24, 124, 224).
 8. Aslender blow-molded plastic bottle (10, 110) according to claim 7,further comprising a plurality of vertically-aligned finger alignmentprotrusions (32, 132) formed integrally on each of said columns (24,124) to define therebetween finger grip locations and to structurallyreinforce said columns (24, 124) at desired locations.
 9. A slenderblow-molded plastic bottle (10, 110) according to claim 7, wherein eachof said panels (22, 122) has a vertical center line and a pair oflateral side edges, and each of said columns (24, 124) has a verticalcenter line and a pair of lateral side edges; wherein, in the as-formedcondition of the bottle (10, 110), each of said panels (22, 122) at saidpanel center line extends radially inward a pre-determined distancerelative to said panel side edges and each of said columns (24, 124) atsaid column center line extends radially outward a pre-determineddistance relative to said column side edges; wherein said column andpanel side edges lie on a cylindrical datum plane (D); and wherein saidpre-determined distances of said panels and columns are substantiallyequal.
 10. A slender blow molded plastic bottle (10, 110) according toclaim 9, wherein said pre-determined distances of said panels (22, 122)and said columns (24, 124) are in the range of about 1 to about 4 mm.11. A slender blow-molded plastic bottle (10) according to claim 7,wherein each of said columns (24) has a substantially rectangularperiphery.
 12. A slender blow molded plastic bottle (110) according toclaim 7, wherein each of said columns (124) has an hourglass-shapedconfiguration with a minimum peripheral extent at about a verticalmedian of the sidewall (116).
 13. A slender blow-molded plastic bottle(10, 110) according to claim 7, wherein each of said panels (22, 122)and each of said columns (24, 124) has upper peripheral edges positionedin an end-to-end array having a substantially circular horizontalcross-sectional shape; and wherein each of said panels (22, 122) andeach of said columns (24, 124) have lower peripheral edges positioned inan end-to-end array having a substantially circular horizontalcross-sectional shape.
 14. A slender blow-molded plastic bottle (10,110) according to claim 13, wherein said sidewall portion (16, 116) hastwo to ten of said panels (22, 122) and an equal number of said columns(24, 124).
 15. A blow-molded slender plastic bottle (10, 110)comprising: a dome (12, 112) having an upper portion with an upstandingsealable finish (18, 118) and a lower portion with a circumferentialgroove providing a waist (20); a base (14, 114); and a tubular sidewall(16, 116) between said dome (12, 112) and said base (14, 114), saidsidewall (16, 116) being formed with a plurality ofcircumferentially-spaced vertically-elongate columns (24, 124) disposedin an alternating pattern with a plurality of circumferentially-spacedsubstantially smooth-surfaced panels (22, 122); each of said columns(24, 124), as formed, being outwardly convex in horizontal cross sectionand each of said panels (22, 122), as formed, being inwardly concave inhorizontal cross section such that each of said panels (22, 122) extendslaterally between and merges directly with an adjacent pair of saidcolumns (24, 124); each of said columns (24, 124), as formed, beingoutwardly convex in vertical cross section and each of said panels (22,122), as formed, being inwardly concave in vertical cross section suchthat each of said columns (24, 124) and panels (22, 122) has oppositeends which merge directly into said dome (12, 112) and base (14, 114) ofthe bottle (10, 110); each of said panels (22, 122) flexing outwardly toexpand the volume of the bottle (10, 110) during hot-filling and each ofsaid panels (22, 122) flexing inwardly in response to a reduction ininternal volume when the bottle (10, 110) is capped and permitted tocool; and said inward deflection of said panels (22, 122) increasing thehorizontal cross-sectional convexity and decreasing the verticalcross-sectional convexity of each of said columns (24, 124) forstructurally enhancing bottle top loading strength.
 16. A blow-moldedslender plastic bottle (10, 110) according to claim 15, furthercomprising a plurality of vertically-aligned outwardly protruding fingeralignment protrusions (32, 132) formed integrally on each of saidcolumns (24, 124) to define finger grip locations and to structurallymodify the strength of said columns (24, 124) at desired locations. 17.A blow-molded slender plastic bottle (10, 110) according to claim 15,wherein each of said panels (22, 122) has a central portion with aperiphery, and each of said columns (24, 124) has a central portion witha periphery; wherein, in the as-formed condition of the bottle (10,110), each of said panels (22, 122) at said central portion extendsradially inward a pre-determined distance relative to said panelperiphery and each of said columns (24, 124) at said column centralportion extends radially outward a pre-determined distance relative tosaid column periphery; and wherein said pre-determined distances of saidpanels (22, 122) and columns (24, 124) are substantially equal.
 18. Ablow-molded slender plastic bottle (10, 110) according to claim 15,having a slenderness ratio of about 3.3:1.
 19. A blow-molded slenderplastic bottle (10, 110) according to claim 15, having upper and lowerbumpers ( 16 a, 16 b, 116 a, 116 b) above and below said sidewall (16,116), and wherein said columns (24, 124), in said bottle as-formedcondition, lie within a cylindrical plane (P) tangent to said bumpers(16 a, 16 b, 116 a, 116 b).
 20. A blow-molded slender plastic bottle(10, 110) according to claim 19, having a cylindrical datum plane (D)coaxial with said first-mentioned cylindrical plane (P) and locatedinwardly thereof, said cylindrical datum plane (D) at said sidewallvertical median defining a reference with respect to which said columns(24, 124) and said panels (22, 122) flex.